I am surely missing something simple here, simply because I don't do this work often enough to hang onto all the details.
My main "default.html" layout file contains these lines.
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.
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<!-- template CSS -->
<link rel="stylesheet" href="/css/styles.css" />
<!-- custom CSS -->
<link rel="stylesheet" href="/css/custom.css" />
<link rel="stylesheet" href="/css/callouts.css" />
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.
.
I see no problem in my /output dir after compilation. Checking the obvious, my three *.css files, newly compiled, are on the server. And they are referred to in my compiled site page files, exactly as indicated in the lines from my layout file above.
Inspecting the page in my browser, however, the CSS is clearly not there.
Someone please tell me what really dumb thing I'm doing that I can't see.
Thank you!
[Using Firefox 68.0.1, on LinuxMint 19.1]